PE Mechanical · HVAC and Refrigeration · checked Oct 29, 2026
The HVAC PE exam, PE Mechanical HVAC & Refrigeration
The HVAC PE exam is the HVAC and Refrigeration module of PE Mechanical: 80 questions and 8 h of testing, all in USCS units. Since October 2025 it follows a new outline of four applied areas, so a guide that still divides it into Principles and Applications is describing the April 2020 edition.
Professional engineer (PE) license from a state boardThe license also needs the board’s experience requirement and any state exams.
NCEES: PE Mechanical exams · NCEES Examinee Guide, May 2026 (PDF) [1][2]
Questions
80 questionsIncludes unscored pretest questions that are not marked.
NCEES: PE Mechanical exams · NCEES: PE Mechanical HVAC and Refrigeration specifications, October 2025 (PDF) · NCEES Examinee Guide, May 2026 (PDF) [1][2][3]
Question types
Multiple choice plus alternative item types (multiple correct, point and click, drag and drop, fill in the blank)No partial credit on alternative items.
NCEES: PE Mechanical exams · NCEES Examinee Guide, May 2026 (PDF) [1][2]
NCEES: PE Mechanical exams · NCEES Examinee Guide, May 2026 (PDF) [1][2]
Exam time
8 hours
NCEES: PE Mechanical exams · NCEES Examinee Guide, May 2026 (PDF) [1][2]
Delivery
Computer-based at Pearson VUE test centersNo online or at-home option.
NCEES: PE Mechanical exams · NCEES Examinee Guide, May 2026 (PDF) [1][2]
When you can test
Year-roundNCEES testing windows run Jan–Mar, Apr–Jun, Jul–Sep and Oct–Dec.
NCEES: PE Mechanical exams · NCEES Examinee Guide, May 2026 (PDF) [1][2]
Units
USCS onlySea-level conditions unless a problem says otherwise.
NCEES: PE Mechanical HVAC and Refrigeration specifications, October 2025 (PDF) [3]
Reference supplied
PE Mechanical reference handbook, on screen as a searchable PDFThe current version is free in your MyNCEES account; NCEES sells no printed copy; on exam day search with the box on the left (Ctrl+F does not work); no personal copies.
NCEES: PE Mechanical exams · NCEES Examinee Guide, May 2026 (PDF) [1][2]
October 2025 editionNo further change appears in the NCEES notice of July 20, 2026, which lists exam changes through fall 2027.
NCEES: PE Mechanical HVAC and Refrigeration specifications, October 2025 (PDF) · NCEES memo to member boards, July 20, 2026: changes through fall 2027 (PDF, Virginia board copy) [3][5]
Four areas since October 2025
Instead of percentages, the specifications publish a question range per area. Equipment and components is the largest at 24–36 items; supportive knowledge is the smallest at 8–12 items, though it grew the most in the new edition. Each area has a page of worked problems.
What changed:October 2025 outline dropped the Principles/Applications split for four applied areas; Supportive Knowledge grew from 3–5 to 8–12 questions and now covers economic analysis and electrical concepts; psychrometrics now include low-temperature processes and equipment adds thermal storage.
A review book written to the April 2020 outline still teaches most of the engineering, but it gives stand-alone thermodynamics, heat transfer and fluids a weight they no longer have, and it under-weights economics and electrical questions. The side-by-side list is on exam facts.
4 problems to start with
0 / 4 answered · 0 correct
Question 1 of 4 · HVAC Loads and Psychrometrics · 18–27 items
An indirect evaporative cooler with a wet-bulb effectiveness of 90% cools outdoor air entering at 95°F dry-bulb. The secondary (scavenger) air is outdoor air at 75°F wet-bulb. What supply air dry-bulb temperature does the cooler deliver?
Given
Wet-bulb effectiveness ε = 90 %
Primary air entering dry-bulb = 95 °F
Secondary air wet-bulb = 75 °F
Find
Supply air dry-bulb (°F)
Solution
Ts = Tdb − ε(Tdb − Twb,sec)
Ts = 95 °F − 0.90 × (95 − 75) °F = 77 °F
Indirect cooling adds no moisture, so the wet-bulb limit belongs to the secondary stream.
About 73°F subtracts the 2°F approach from the wet-bulb instead of adding it — below the wet-bulb, which no evaporative cooler reaches.
About 75°F is the secondary-air wet-bulb, reachable only at 100% effectiveness; the 90% rating leaves an approach.
About 77°F: the primary air closes 90% of the 20°F gap between its dry-bulb and the secondary-air wet-bulb, leaving 2°F.
About 93°F applies the effectiveness backwards: it removes only 10% of the 20°F potential, 95 − 0.1 × 20.
Question 2 of 4 · HVAC and Refrigeration Distribution and Systems · 20–30 items
What control strategy is most effective for maintaining indoor air quality in spaces with highly variable occupancy?
Solution
Outdoor air ∝ CO2 rise above outdoor (people-driven); ASHRAE 62.1 allows the people component to reset with occupancy.
A time schedule cannot follow occupancy that varies unpredictably; it over- or under-ventilates whenever the room departs from the schedule.
An economizer controls outdoor air for free cooling by temperature; it does not respond to how many people are present.
A fixed rate at peak occupancy keeps air quality but wastes conditioning energy for most hours, when the room is partly empty.
CO2-based demand control tracks actual occupancy, raising outdoor air when the room fills and cutting it when it empties.
Question 3 of 4 · HVAC Equipment and Components · 24–36 items
A chilled water cooling coil experiences a 25% reduction in its overall heat transfer coefficient (UA) due to water-side fouling. Assuming the entering air temperatures, entering water temperatures, and mass flow rates remain entirely constant, how does the total sensible and latent cooling capacity (Q) change relative to the clean condition?
Solution
q = UA · LMTD (or q = ε·Cmin·ΔTmax with ε = f(NTU), NTU = UA/Cmin)
ε rises less than in proportion to NTU, so a 25 % drop in UA cuts q by less than 25 %.
Fouling adds thermal resistance; it cannot increase the heat transferred.
Capacity cannot fall faster than UA here, because the driving temperature difference rises, not falls.
Capacity depends on UA; a fouled coil with the same entering conditions removes less heat.
Exactly 25% would hold only if the temperature difference stayed fixed; it grows as UA falls.
Less than 25%: with lower UA the leaving water stays colder and the air warmer, which widens the temperature difference and partly offsets the lost UA.
Question 4 of 4 · HVAC Equipment and Components · 24–36 items
What is the primary purpose of a thermal energy storage system in an HVAC application?
Solution
TES: make cooling off-peak (ice or chilled water), discharge on-peak → lower kW demand and cost.
Loop temperature stability comes from chiller controls; storage is an energy-cost and demand measure.
Ice or chilled water made at night is melted during the day, so the chiller runs less at peak and demand charges fall.
Stored cooling can ride through short outages, but the pumps still need power; this is not why systems are installed.
Storage does not raise a chiller's rating; it lets a smaller chiller meet a peak with help from the tank.
Answer every question to see your score
Three PE Mechanical modules, one of them HVAC&R
PE Mechanical is three separate exams with the same format and fee, and you register for one. HVAC and Refrigeration is the building-services module: loads, air and water systems, refrigeration and the equipment that serves them. Thermal and Fluid Systems keeps a principles area and adds power systems and fluid equipment; Machine Design and Materials is about stress, joints, power transmission and components.
Of the three, only HVAC and Refrigeration is USCS only; the other two modules use SI + USCS. This site has practice for HVAC and Refrigeration so far; the other two appear in the table as fact cards.
Checked Oct 29, 2026. Sources are numbered and listed under Source notes.
Attribute
6PE Mechanical HVAC & Refrigeration
PE Mechanical Thermal & Fluid Systems
PE Mechanical Machine Design & Materials
Source
Checked
Units
USCS onlySea-level conditions unless a problem says otherwise.
First-time pass rateLatest half-year on the NCEES exam page. FE: first-time takers from EAC/ABET programs within 12 months of graduation. PE: all first-time takers under member boards.
71%First-time takers under NCEES member boards, Jan–Jun 2026 (799 takers; NCEES table updated July 2026).
70%First-time takers under NCEES member boards, Jan–Jun 2026 (578 takers).
61%First-time takers under NCEES member boards, Jan–Jun 2026 (401 takers).
The Model Law sets the standard order: a degree, the FE, an engineer-intern certificate, experience and then the PE. Experience under the Model Law:4 years (EAC/ABET degree). Boards adopt their own versions, and two differences matter most: each board decides whether you may take the PE before the experience is complete, and some boards add state exams before the license.
The FE discipline closest to HVAC work is FE Mechanical.
FE and PE side by side on level, length and fee: FE vs PE.
What this exam's pages cover, and what they leave to others
The HVAC application of psychrometrics, loads, ducts and piping, refrigeration systems, HVAC controls, equipment selection and building acoustics is explained on the four area pages here. The underlying theory has one home page each:
No personal references are allowed. The exam gives you one reference on screen, the PE Mechanical reference handbook, and this module gets no design standards. How to work with it: reference handbook.
What is the HVAC&R question count?
80, and you answer every one; a few are unscored pretest items that look like the rest. Timing and scoring: exam facts.
How many first-timers pass the HVAC&R exam?
71% of 799 first-time takers passed in Jan–Jun 2026, on the table the exam owner updated in July 2026. Repeat takers and annual figures are on exam facts.
Does the exam use SI units?
No: USCS only, and sea level is assumed unless a problem gives an elevation.
HVAC&R problems on your phone
PE Mechanical HVAC & Refrigeration questions, answers and worked solutions in a study app.